An Indonesian National Search and Rescue Agency personnel scans the seas aboard a boat on patrol in the Malacca Strait off Aceh province located in the area of northern Sumatra island on March 12, 2014 during the continued search for the missing Malaysia Airlines flight MH370. The search for a missing Malaysian jet swung northwest towards the Andaman Sea on March 12, far from its intended flight path, exposing Malaysia to mounting criticism that its response was in disarray. AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

An Indonesian National Search and Rescue Agency personnel scans the seas aboard a boat on patrol in the Malacca Strait off Aceh province located in the area of northern Sumatra island on March 12, 2014 during the continued search for the missing Malaysia Airlines flight MH370. (credit: STR/AFP/Getty Images)

WASHINGTON (CBS NEWS/CBSDC/AP) — CIA Director John Brennan believes that terrorism shouldn’t be ruled out in the disappearance of Malaysia Airlines Flight 370.

“I wouldn’t rule it out. Not at all,” Brennan told an audience at the Council on Foreign Relations Tuesday.

The Boeing 777 carrying 239 people disappeared early Saturday morning after taking off from Kuala Lumpur for Beijing. The flight fell off civilian radar screens at 1:30 a.m. about 35,000 feet above the Gulf of Thailiand between Malaysia and southern Vietnam. It sent no distress signals or any indication it was experiencing any problems.

Brennan called the disappearance a disturbing mystery.

“I think there’s a lot of speculation right now – some claims of responsibility that have not been confirmed or corroborated at all. We are looking at it very carefully … working with FBI and TSA and others,” Brennan said. “Our Malaysian counterparts are doing everything they can to try to put together the pieces here, but clearly, there’s still a mystery which is very disturbing. And until we actually can find out where that aircraft is, we might have an opportunity to do some forensic analysis that will lead us in the right direction.”

Authorities in fact haven’t ruled out any possible cause, including mechanical failure, pilot error, sabotage or terrorism. Both the Boeing 777 and Malaysia Airlines have excellent safety records. Until wreckage or debris is found and examined, it will be very hard to say what happened.

Malaysian authorities have since said that air defense radar picked up traces of what might have been the plane turning back and flying until it reached the Strait of Malacca, a busy shipping lane west of the narrow nation some 250 miles from the plane’s last known coordinates.

Military and government officials on Wednesday said American experts, and the manufacturer of the radar systems, were examining that data to confirm it showed the Boeing 777. Until then, they said the search would continue on both sides of the country, with an equal focus.

Dozens of ships and planes searching waters have failed to turn up anything, prompting officials to expand the hunt. Malaysia asked India to join the search for the missing jet in waters near the Andaman Sea — far to the northwest of its last reported position.

“As of today, we have not found anything, but we are extending (the search) further,” Hishammuddin said.

CBS News correspondent Bob Orr says the U.S. government has offered wide-ranging assistance, including investigators from the FBI, FAA and NTSB. But, so far the Malaysians have not asked for help, and have shared little about the investigation.

Air force chief Gen. Rodzali Daud said air defense radar showed an unidentified object at 2:15 a.m. about 200 miles northwest of Penang.

“I am not saying it’s flight MH370. We are still corroborating this. It was an unidentifiable plot,” he said.

It’s unlikely the plane would have flown across Malaysia without being detected by civilian radar unless its electrical systems, including transponders allowing it to be identified by radar, were either knocked out or turned off.

Orr says veteran crash investigators have been confounded by the Malaysian military reports on the radar sighting.

If it did in fact change direction so dramatically to the southwest, the jet might have flown hundreds of miles off course without maintaining radio or data contact with controllers.

For that to be possible, experts say the plane must have either suffered an electrical failure that disabled the transponder which reports location, altitude, and speed, or somebody in the cockpit deliberately turned it off. Orr says that’s why investigators cannot rule out hijacking or a criminal act by the flight crew at this stage.

Malaysian authorities had contacted their Indian counterparts seeking help in searching areas near the Andaman Sea, India’s ministry of external affairs spokesman Syed Akbaruddin said.

Hishammuddin praised India for joining the efforts and vowed to keep up the search until the plane was found.

Earlier, Gen. Rodzali released a statement denying remarks attributed to him in a local media report saying that military radar had confirmed that aircraft flew west over and made it to the Malacca strait. The Associated Press contacted a high-level military official, who confirmed the remarks.

Indonesia air force Col. Umar Fathur said the country had received official information from Malaysian authorities that the plane was above the South China Sea, about 12 miles from Kota Bharu, Malaysia, when it turned back toward the strait and then disappeared. That would place its last confirmed position closer to Malaysia than has previously been publicly disclosed.

Confusion over whether the plane had been spotted flying west has prompted speculation that different arms of the government have different opinions over where the plane is most likely to be, or even that authorities are holding back information.

Asked about this, Hishammuddin said his government had been transparent from the start.

“There is only confusion if you want to see confusion,” he said.

Choi Tat Sang, a 74-year-old Malaysian man, said the family is still holding out hope that the plane and all on board are safe. His daughter in law, Goh Sock Lay, 45, is the chief stewardess on the flight. Her 14-year-old daughter, an only child, has been crying every day since the plane’s disappearance.

“We are heartbroken. We are continuing to pray for her safety and for everyone on the flight,” he said.

The mother of passenger Zou Jingsheng, who would only give her name as Zou, wept and spoke haltingly about her missing son while staying at a hotel near the Beijing airport. She expressed frustration with the airline and the Malaysian government over their handling of the case.

“I want to talk more, but all this is very stressful, and after all it is my son’s life that I am concerned about. I just want to know where he is, and wish he is safe and alive,” she said.